&#34;deli&#34; bag with extra thin walls and increased strength and method of manufacturing same

ABSTRACT

“Deli” bags are formed by extruding first and second aligned sheets of high density polyethylene film having a thickness no greater than 0.0008 inches. The aligned sheets are heat sealed along the sides and either the top or bottom edges to form each bag. After printing indicia on the wall of each bag, mating closure tracks are created. The tracks are situated proximate the non-sealed top or bottom of the bag. A closure member in the form of a slide or zipper is installed as the bags are separated and stacked. The closure member co-operates with the closure tracks to open and close the bag. Preferably, four side-by-side bags can be processed at the same time, increasing efficiency and reducing manufacturing cost. The bags have extra thin walls, increased strength and keep food fresher.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to plastic “deli” bags and moreparticularly to a “deli” bag formed of extra thin sheets of high densitypolyethylene which has increased strength and the ability to keep foodproducts fresh longer, and to a method of manufacturing same.

2. Description of Prior Art Including Information Disclosed Under 37 CFR1.97 and 1.98

“Deli” bags made of low density plastic sheet materials are well knownin the art. The bags are used for various applications includingpackaging meat or other products purchased from retail foodestablishments. The bags are used to transport the food products to thehome of the purchaser and to preserve of the contents once at home.Slide or zipper-type closures are commonly provided to seal the openmouth of the bags to preserve freshness.

Conventional “deli” bags are fabricated using a three step process inwhich the tracks for the slide or zipper closure are extruded as part ofthe plastic film by the blow film machine in the extrusion process. Thebags are printed two at a time and then the slide or zipper isinstalled.

However, that manufacturing process is relatively slow. The time periodover which the bags produced by that process can maintain freshness islimited. Further, the strength of the bags many not be adequate for allapplications.

It is therefore a prime object of the present invention to provide a“deli” bag with extra thin walls and increased strength.

It is another object of the present invention to provide a “deli” bagwhich is capable of maintaining the freshness of its contents for alonger time period than conventional bags.

It is another object of the present invention to provide a “deli” bagformed of high density polyethylene.

It is another object of the present invention to provide a “deli” bag inwhich the walls of the bag are no more than 0.0008 inch thick.

It is another object of the present invention to provide a “deli” bagusing a manufacturing process which is more efficient and less expensivethan conventional manufacturing processes.

It is another object of the present invention to a method ofmanufacturing a “deli” bag in which either top loaded or bottom loadedbags can be produced.

It is another object of the present invention to provide a method ofmanufacturing a “deli” bag in which the closure tracks are created afterthe bags are formed.

It is another object of the present invention to provide a method ofmanufacturing a “deli” bag in which the closure tracks are created aftercompletion of the printing process.

It is another object of the present invention to provide a method ofmanufacturing a “deli” bag same in which four production lines of “deli”bags can operate simultaneously.

BRIEF SUMMARY OF THE INVENTION

In general, the above object are achieved by the present invention whichis directed to a method of manufacturing plastic “deli” bags includingextruding first and second aligned sheets of high density polyethylenefilm. The sheets are formed into plastic bags films by heat sealing thealigned sheets along the sides and either the top or bottom edges ofeach bag. Mating closure tracks are created proximate the non-sealed topor bottom of each bag after the bag is formed. A closure member is theninstalled to co-operate with the closure tracks to open and close thebag.

In accordance with another aspect of the present invention, a method isprovided for manufacturing plastic “deli” bags. The method includesextruding aligned sheets of plastic film each having a thickness of nomore than 0.0008 inch. The bags are formed from the aligned sheets byheat sealing the side and either the top or bottom edges of each bag.Mating closure tracks are created proximate the non-sealed top or bottomof each plastic bag, after the bag is formed. A closure member isinstalled to co-operate with the closure tracks to open and close thebag.

The step of installing the closure member can include installing eithera slider member or a zipper member.

The manufacturing method further includes printing indicia on each ofthe bags. Preferably, four bags in side-by-side relation are printed atthe same time.

The step of extruding aligned sheets of film includes extruding a firstset aligned film sheets with a width at least as wide as twoside-by-side “deli” bags. It also includes extruding a second set ofaligned film sheets with the width at least as wide as two side-by-side“deli” bags. The step of printing indicia includes arranging the firstset of aligned film sheets and the second set of aligned film sheets inside-by-side relation such that indicia for four “deli” bags can beprinted at the same time.

In accordance with another aspect of the present invention, a plastic“deli” bag is provided including first and second aligned sheets of highdensity polyethylene film sealed along the sides and either the top orbottom edges. The bag has mating closure tracks proximate the non-sealedtop or bottom edge thereof. A closure member is provided to co-operatewith the closure tracks to permit the bag to be opened and closed.

In accordance with another aspect of the present invention, a plastic“deli” bag is provided including first and second aligned plastic sheetswith a thickness of no more than 0.0008 inch sealed along the sides andeither the top or bottom edges. The bag has mating closure tracksproximate the non-sealed top or bottom edge thereof. A closure member isprovided to co-operate with the closure tracks to permit the bag to beopened and closed.

The bag closure member is either a slide member or a zipper member.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF DRAWINGS

To these and to such other objects that may hereinafter appear, thepresent invention relates to a “deli” bag with extra thin walls andincreased strength, and a method of manufacturing same, as described indetail in the following specification and recited in the annexed claims,taken together with the accompanying drawings, in which like numeralsrefer to like parts and in which:

FIG. 1 is an idealized side view of a production line for manufacturingbags in accordance with the present invention;

FIG. 2 is an idealized top view of the production line of FIG. 1; and

FIG. 3 is a perspective view of a bag of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 3 shows the “deli” bag of the present invention, generallydesignated A. The bag includes a front wall 10, a rear wall 12, an open(non-sealed) top 14, a sealed bottom 16, a left side edge 18 and a rightside edge 20. The edges 18, 20 of the front wall 10 and the rear wall12, and bottom edge 16 are sealed to each other to form an open topenclosure adapted to receive a food product or the like.

The bag shown in FIG. 3 is loaded through the open top 14. However,bottom loading bags, in which top 14 is sealed and bottom 16 is open,can be fabricated by the process of the present invention with simplemodifications well within the knowledge of those skilled in the art.

The interior surfaces of front wall 10 and rear wall 12 proximate openmouth 14 of the bag are provided with opposing, mating closure tracks22. A closure member 24, in the form of a slide or a zipper, isinstalled such that movement of the member along the top of the bag willopen and close mouth 14.

The walls 10 and 12 are formed of high density polyethylene, a materialwith a high strength-to-density ratio. It has stronger intermolecularforces and higher tensile strength as compared to low density plasticsheets. It is also harder, more opaque and can withstand highertemperatures. At the same time, the material is resistant to manysolvents.

Further, the properties of high density polyethylene keep food situatedwithin the bag fresher than conventional plastic materials. Accordingly,it is an ideal material for use in “deli” bags.

FIGS. 1 and 2 illustrate the manufacturing process of the presentinvention. The process includes a feed stage in which first and secondaligned sheets 30, 32 of extruded high density polyethylene film havinga thickness of no more than 0.0008 inches are feed from rollers 34, 36to the top surface of a conveyor 38. The closure tracks are not formedduring the extrusion process, as is the case in conventional fabricationmethods.

In the sealing stage, the aligned sheets 30 and 32 pass beneath a heatedreciprocating platen 40 in order to form bags A. The platen heat sealsthe aligned sheets to join the side edges 18, 20 and bottom 16 of eachbag. As these bags are top loading bags, the edges of the walls whichdefine mouth 14 are not sealed together.

The bags then move along conveyer 38 to a print stage where they passbeneath one or more a print rollers 42 (only one of which is shown). Theprint rollers deposit ink in the form of text and/or images (such as thelogo of the store in which the bags are used) on the exterior surface ofthe front wall of each bag.

After printing, the bags move through a process stage in which the bagsare separated from each other by a blade and at the same time theclosure tracks 22 are created. This is accomplished using areciprocating platen 44 which includes a downwardly directed blade 46and elongated heated protrusions 48 extending from the bottom surface.Thus, in the process of the present invention, the closure tracks arecreated after the bags are formed.

In the last stage of the manufacturing process, each of the separatebags A moves off the end of conveyor 38 and onto a platform 50 to form astack of bags A. As each of the bags is situated on the stack, a closuremember 24 in the form of a plastic slide or zipper is installed on thetop of the bag such that the non-sealed mouth 14 of the bag can beopened and closed.

Referring now to FIG. 2, which is a top view of conveyor 38 and theassociated fabrication stages, feed rolls 34 and 36 are provided in setseach feeding aligned sheets two bag widths wide to a different one oftwo reciprocating sealing platens 40 in the sealing station. The bagsexit the sealing station in four side-by-side lines. The four lines arefed to a print roller 42. Roller 42 extends across the entire width ofthe conveyor such that four bags can be printed at one time. Afterprinting, the bags pass under two platens 44 where they are separated bya blade and the closure tracks are created.

As the separated bags move off the end of conveyor 38 and onto a stackof bags accumulating on a platform 50, a closure member 24 is installedon each bag. The stacks of bags A typically contain 50 or 100 bags eachand are now ready for packaging and shipment.

While only a single preferred embodiment of the present invention hasbeen disclosed for purposes of illustration, it is obvious that manymodifications and variations could be made thereto. It is intended tocover all of those modifications and variations which fall within thescope of the present invention, as defined by the following claims.

I claim:
 1. A plastic deli bag comprising first and second alignedsheets of high density polyethylene film sealed along the sides andeither the top or bottom edges having mating closure tracks proximatethe non-sealed top or bottom edge thereof and a closure memberco-operating with the closure tracks to permit the bag to be opened andclosed.
 2. The bag of claim 1 wherein said closure member is a slidemember.
 3. The bag of claim 1 wherein said closure member is a zippermember.
 4. A plastic deli bag comprising first and second alignedplastic sheets having a thickness of no more than 0.0008 inch heatsealed along the sides and either the top or bottom edges having matingclosure tracks proximate the non-sealed top or bottom edge thereof and aclosure member co-operating with the closure tracks to permit the bag tobe opened and closed.
 5. The bag of claim 4 wherein said closure memberis a slide member.
 6. The bag of claim 4 wherein said closure member isa zipper member.